Dimopoulos IS, et al. - Authors evaluated the safety of a recombinant adeno-associated viral vector expressing REP1 (rAAV2.REP1) in choroideremia subjects. In six subjects treated with a subfoveal injection of AAV2.REP1, they experienced 1 serious adverse event. A decline in the area of remaining functional RPE in the treated eye and untreated eye was seen at the same rate over a 2 year period. A remarkably predictive biomarker was fundus autofluorescence area. No change was shown by microperimetry sensitivity or significant change up to 2 years after vector administration.